Description: Add 3 new sysfs entries to nbd.

# cat /sys/block/nbd6/nbd/peer 
127.0.0.1
# cat /sys/block/nbd6/nbd/flags 
0
# cat /sys/block/nbd6/nbd/xmit_timeout 
6

This patch depends on patch nbd-sysfs-framework.diff

From: Paul Clements <paul.clements@steeleye.com>
Signed-off-by: Paul Clements <paul.clements@steeleye.com>
---

 nbd.c |   79 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 77 insertions(+), 2 deletions(-)

diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 23f3619..44cd41d 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -136,7 +136,7 @@ static void sock_shutdown(struct nbd_device *lo, int lock)
 		mutex_unlock(&lo->tx_lock);
 }
 
-static void nbd_xmit_timeout(unsigned long arg)
+static void xmit_timeout(unsigned long arg)
 {
 	struct task_struct *task = (struct task_struct *)arg;
 
@@ -183,7 +183,7 @@ static int sock_xmit(struct nbd_device *lo, int send, void *buf, int size,
 
 			if (lo->xmit_timeout) {
 				init_timer(&ti);
-				ti.function = nbd_xmit_timeout;
+				ti.function = xmit_timeout;
 				ti.data = (unsigned long)current;
 				ti.expires = jiffies + lo->xmit_timeout;
 				add_timer(&ti);
@@ -719,16 +719,91 @@ struct nbd_sysfs_entry {
 	ssize_t (*store)(struct nbd_device *, const char *, size_t);
 };
 
+static ssize_t
+peer_show(struct nbd_device *lo, char *page)
+{
+	struct socket *sock = lo->sock;
+	struct sockaddr_storage addr;
+	struct sockaddr *sa = (struct sockaddr *)&addr;
+	struct sockaddr_in *sin = (struct sockaddr_in *)&addr;
+	struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&addr;
+	int err, len;
+
+	if (!sock)
+		goto err;
+
+	err = kernel_getpeername(sock, sa, &len);
+	if (err < 0)
+		goto err;
+
+	if (sa->sa_family == AF_INET6)
+		return sprintf(page, "%pI6\n", &sin6->sin6_addr);
+	else if (sa->sa_family == AF_INET)
+		return sprintf(page, "%pI4\n", &sin->sin_addr);
+err:
+	return 0;
+}
+
 static ssize_t pid_show(struct nbd_device *lo, char *page)
 {
 	return sprintf(page, "%ld\n", (long)lo->pid);
 }
 
+static ssize_t
+flags_show(struct nbd_device *lo, char *page)
+{
+	return sprintf(page, "%x\n", lo->flags);
+}
+
+static ssize_t
+flags_store(struct nbd_device *lo, const char *buf, size_t len)
+{
+	long n;
+
+	if (strict_strtol(buf, 16, &n))
+		return -EINVAL;
+
+	lo->flags = n;
+
+	return len;
+}
+
+static ssize_t
+xmit_timeout_show(struct nbd_device *lo, char *page)
+{
+	return sprintf(page, "%d\n", lo->xmit_timeout / HZ);
+}
+
+static ssize_t
+xmit_timeout_store(struct nbd_device *lo, const char *buf, size_t len)
+{
+	long n;
+
+	if (strict_strtol(buf, 10, &n))
+		return -EINVAL;
+
+	lo->xmit_timeout = n * HZ;
+
+	return len;
+}
+
+static struct nbd_sysfs_entry nbd_peer =
+__ATTR(peer, S_IRUGO, peer_show, NULL);
+
 static struct nbd_sysfs_entry nbd_pid =
 __ATTR(pid, S_IRUGO, pid_show, NULL);
 
+static struct nbd_sysfs_entry nbd_flags =
+__ATTR(flags, S_IRUGO|S_IWUSR, flags_show, flags_store);
+
+static struct nbd_sysfs_entry nbd_xmit_timeout =
+__ATTR(xmit_timeout, S_IRUGO|S_IWUSR, xmit_timeout_show, xmit_timeout_store);
+
 static struct attribute *nbd_default_attrs[] = {
+	&nbd_peer.attr,
 	&nbd_pid.attr,
+	&nbd_flags.attr,
+	&nbd_xmit_timeout.attr,
 	NULL,
 };